1. Field of the Invention
The present invention relates to a semiconductor photodetector and a photodetecting device.
2. Related Background Art
High-speed response characteristics are being demand more than ever in recent years in the field of optical semiconductor devices, and especially photodetectors. Demands for high-speed response, high S/N ratio, low cost, etc., for various wavelengths of light emitting devices are becoming stronger especially with photodetectors for information communication that send and receive large volumes of information.
For example, Patent Document 1 discloses a PIN photodiode for optical communication that is equipped with high-speed response characteristics. With this PIN photodiode, an N-type semiconductor region of high resistivity is epitaxially grown on an N-type semiconductor substrate of low resistivity. In this N-type semiconductor region (epitaxial layer), a photodetecting region is formed from a P-type semiconductor region. The N-type and P-type semiconductor regions form a PN junction that is used by applying a reverse bias.
Conventionally, a PIN photodiode with such an arrangement is positioned inside a can package. Since this can type optical semiconductor device is not suited for achieving thinness and compact size, it cannot meet the compactness requirements demanded in the information communication field. Molded devices, aimed at achieving compact size, are thus beginning to be developed. Photodetectors described in the following Patent Document 2 and Patent Document 3 are also known.
Patent Document 1: Japanese Published Unexamined Patent Application No. Hei 5-67800
Patent Document 2: Japanese Published Unexamined Patent Application No. Hei 4-242980
Patent Document 3: Japanese Published Unexamined Patent Application No. Sho 51-057174